PROJECT SUMMARY Cigarette smoking is the leading preventable cause of morbidity and mortality in the U.S. and is the leading cause of cancer. Alcohol use is also a primary preventable cause of cancer, with alcohol accounting for 50-80% of specific types of cancer. Importantly, the combined use of cigarettes and alcohol is associated with an increased risk of mortality and cancer development, as 75% of head and neck cancers are attributable to the combined use of cigarettes and alcohol. Moreover, about 16% of smokers report heavy alcohol use compared to only 3.5% of nonsmokers. The current proposal will first modify an existing mindfulness-based intervention for substance use to include a focus on smoking and alcohol use, followed by testing the revised treatment on a small sample of participants to determine the feasibility and acceptability of the treatment. Interventions that effectively target both smoking and alcohol use have the potential to greatly decrease cancer risk and increase life expectancy. Mindfulness has been conceptualized as attending purposefully to emotions/thoughts/sensations in the present moment without labelling them as good or bad (e.g., nonjudgment), and has been linked to decreased stress and negative affect. Furthermore, mindfulness-based treatments have been associated with increased smoking abstinence and decreased alcohol use, as well as key constructs implicated in relapse including negative affect, self-efficacy, and craving. Thus, mindfulness-based interventions not only have the ability to increase success in quitting smoking and decreasing alcohol use, but also have the potential to reduce risk of relapse and promote maintenance of behavior change following treatment. The objective of this R34 proposal is to modify and test a mindfulness-based treatment designed to reduce alcohol use and increase smoking abstinence. The target population is cigarette smokers who engage in binge drinking, and who are interested in changing both behaviors. This project will first modify an existing mindfulness treatment to include a focus on smoking and alcohol use (Study 1). Protocol modification will be conducted through an iterative development process based on the existing literature, expertise of the research team, and feedback from two small groups of participants (N=16). Study 2 will examine specific benchmarks associated with the feasibility and acceptability of this treatment among a sample of our target population (N=64). We will collect data on proximal and distal outcomes from participants randomized to Mindfulness-Based Relapse Prevention for Smoking and Alcohol Use (MBRP-SA) or Cognitive Behavioral Therapy. This project is innovative, as it will be one of the first to develop a mindfulness-based treatment as a first-line intervention tailored to target smoking and binge drinking in adults. The current study will provide pertinent information regarding the acceptability and feasibility of the treatment protocol and data collection process. Although future work will be needed to evaluate the efficacy and effectiveness of the treatment, we know that interventions that effectively target both smoking and alcohol use through common mechanisms have the potential to greatly decrease cancer risk and increase life expectancy.